Rubio hopes role as last happy Republican is path to victory

The Republican candidates in the 2016 presidential race are, by and large, not a very cheery bunch. Donald Trump has disparaged more people than King Lear, Chris Christie has reveled in verbally brawling with hecklers and Lindsey Graham appears perennially on the cusp of declaring war. After seven years of seeing a Democrat in the White House, that rhetoric fits the Republican mood pretty well.